In the loading, transfer and safe storage of bulk liquids, such as in the tanks of ships and barges and stationary storage tanks, it is important to provide operators with clear and accurate indications of liquid levels and liquid temperatures. Bulk liquid and handling facilities often employ line-powered largescale remotely monitored systems for providing indications of liquid level and temperature and alarm conditions. However, it is often required to monitor level and temperature at the tank facility or at local outdoor pump or valve control stations. Such local sites are often exposed to hostile ambient conditions such as on the decks of a ship. Heretofore, information on material level and temperature was obtained manually by use of a dip stick or hand line inserted through an open access port in the top of the tank to provide a measure of liquid level, or insertion of a thermometer into the tank for measurement of temperature. The opening of such access ports can be extremely hazardous to the operator by exposure to vapors that can be toxic and by increasing the risk of vapor and liquid pollution from the opened tank, and in addition can be violative of safety laws. Liquid transfer on ships and on tank farms, especially where complex inflow and outflow operations are being performed simultaneously, can result in serious spillage if accurate monitoring of level is not provided continuously during such operations.